Preheat oven to 400 degrees. Cover two large baking sheets with parchment paper. Cut off ends of butternut squash, peel and cut into 1 inch cubes.
Place in large bowl, add 4 tbsp olive oil to bowl. Toss until squash is all coated with olive oil.
Spread butternut squash evenly on covered baking sheets. Place in oven. Cook 20 - 25 minutes, then turn and cook an additional 20 - 25 minutes. Making sure to watch butternut squash closely towards the end of roasting time. Remove from oven when it has achieved a deep golden brown; being careful it doesn't become overly browned and/or crispy.
Meanwhile, over med-low heat saute' onion in soup pot in remaining 1 tbsp olive oil, until clear. Add chopped garlic, saute' for and addition 1 to 1 1/2 mins., stirring constantly to avoid garlic burning. Remove from heat, pour onion and garlic mixture into blender jar.
Place roasted butternut squash from oven into blender jar with onion and garlic. Add 4 cups of broth, blend until creamy, then pour into soup pot. This may be done in batches.
On low heat, add remaining broth to blended butternut squash mixture. Add next four ingredients. Simmer for 10 - 15 minutes to heat thoroughly and meld flavors.
Optional: Serve in bowl and garnish with 1 tbsp heavy cream. For a decorative appearance, lightly pour cream in center of bowl and make a swirly design in it by dragging a butter knife through it in a circular motion.
